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Methods for instantaneous speed estimation in ultrasonic object detection
Šilar, Adam ; Pikula, Stanislav (referee) ; Havránek, Zdeněk (advisor)
The main goal of this master thesis is to explore suitable methods for estimating the instantaneous velocity of a moving object. The estimation of instantaneous velocity is based on the knowledge of the Doppler effect, which causes a shift in the frequency of ultrasound to another frequency depending on the velocity. Using the knowledge of the Doppler effect, a procedure is described for designing and programming a generator of simulated ultrasound data in the LabVIEW environment. The thesis theoretically describes methods for estimating instantaneous velocity, and selected methods are applied to test data to obtain information about the object's instantaneous velocity. The selected methods are tested for various parameters and compared with each other. The methods were subsequently practically tested on real measured data and compared with their simulated versions.
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Condition monitoring technique for smart diagnostics
Dostálek, Jakub ; Čala, Martin (referee) ; Pikula, Stanislav (advisor)
This thesis deals with the use of the Teager-Kaiser energy operator (TKEO) for state monitoring and testing its use for determining the instantaneous frequency and amplitude in comparison with the results of other methods (e.g. with the Hilbert-Huang transform method) and for this comparison uses various simulated and real signals. This process is programmatically implemented in LabVIEW, and tests are designed and programmatically implemented to evaluate the pros and cons of using these methods to determine the instantaneous frequency and amplitude for different kinds of signals.
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Measurement of dynamic quality of gradient magnetic fields
Kabrda, Miroslav ; Kubásek, Radek (referee) ; Bartušek, Karel (advisor)
In the first chapter of bachelor thesis I focused on description the tomograph construction. The next chapter deals with the measurement of gradient magnetic fields, using methods based on instantaneous frequency. The thesis describes: the IF method, the IFSE method ( the method of measuring the instantaneous frequency of the spin echo), the IFSES method (the instantaneous frequency measurement method for a series of spins) and the method of Gradient decay measurement in NMR tomography. Each method describes the basic principles of the measurement, the excitation pulse sequence, obtainment of instantaneous frequency and the method of evaluation of the obtained signal. This bachelor thesis includes experimental measurements using the method of Gradient decay measurement in NMR tomography. The experimental data obtained are given and evaluated in the last chapter at the end of the thesis.
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Signal Decomposition using EMD transform
Mžourek, Zdeněk ; Mekyska, Jiří (referee) ; Smékal, Zdeněk (advisor)
Aim of this thesis is to introduce empiric mode decomposition as a method for decomposing arbitrarily nonlinear and non-stationary signal into intrinsic mode functions. Using empiric modal decomposition together with Hilbert transform produces instantaneous frequency. We can use this instatenous frequency to create a Hilbert spectrum and use it for analysis in time-frequency domain. In next part we show several drawbacks of this method. We also present several ways how to improve empirical mode decomposition algorithm to obtain better results. An example of decomposition by empiric mode decompositon is made to illustrate how the whole procedure works.
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Signal Decomposition using EMD transform
Mžourek, Zdeněk ; Mekyska, Jiří (referee) ; Smékal, Zdeněk (advisor)
Aim of this thesis is to introduce empiric mode decomposition as a method for decomposing arbitrarily nonlinear and non-stationary signal into intrinsic mode functions. Using empiric modal decomposition together with Hilbert transform produces instantaneous frequency. We can use this instatenous frequency to create a Hilbert spectrum and use it for analysis in time-frequency domain. In next part we show several drawbacks of this method. We also present several ways how to improve empirical mode decomposition algorithm to obtain better results. An example of decomposition by empiric mode decompositon is made to illustrate how the whole procedure works.
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Measurement of dynamic quality of gradient magnetic fields
Kabrda, Miroslav ; Kubásek, Radek (referee) ; Bartušek, Karel (advisor)
In the first chapter of bachelor thesis I focused on description the tomograph construction. The next chapter deals with the measurement of gradient magnetic fields, using methods based on instantaneous frequency. The thesis describes: the IF method, the IFSE method ( the method of measuring the instantaneous frequency of the spin echo), the IFSES method (the instantaneous frequency measurement method for a series of spins) and the method of Gradient decay measurement in NMR tomography. Each method describes the basic principles of the measurement, the excitation pulse sequence, obtainment of instantaneous frequency and the method of evaluation of the obtained signal. This bachelor thesis includes experimental measurements using the method of Gradient decay measurement in NMR tomography. The experimental data obtained are given and evaluated in the last chapter at the end of the thesis.
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Filtering of MR signal in NMR tomography
Bartušek, Karel ; Geschneidtová, E.
The paper presents the comparison of three filtering techniques tested for the nuclear magnetic resonance tomography signal processing. FIR filtering, Wavelet and adaptive filtering were applied in a tomograph designed and produced in the Institute of Scientific Instruments of the Academy od Sciences of the Czech Republic. The test results obtained are described in the next chapters.
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